Combinatorial weighing apparatus

ABSTRACT

A weighing assembly includes a hopper for central loading of the articles to be packaged, a channel for conveying the articles from the hopper radially, a member for weighing the articles to be packaged in the form of a plurality of weighing baskets placed peripherally and having lower outlets for discharging the weighed portions of the articles, and, below the weighing baskets, a member for conveying weighed portions of the articles received via the lower discharge outlets of the weighing baskets in the form of at least one first part for peripheral transport of the articles. The first part has a surface for supporting and transporting the articles to be packaged positioned below and in proximity of the transfer outlets of corresponding weighing baskets and defines a peripheral conveying path.

FIELD OF THE INVENTION

The present invention relates to a weighing assembly which can be usedpreferably, but not exclusively, in a packaging machine.

BACKGROUND OF THE INVENTION

The invention relates to an improvement of the weighing assemblies ofthe radial type, that is to say of the type developing with a column orvertical structure comprising at the top a single point for centralfeeding of the material to be packaged and having as characteristicelement a substantial radial symmetry of the various parts which make upthis assembly.

This kind of weighing assembly has become established on the market dueto its characteristics of speed of feeding the material to be packaged,of restricting overall dimensions on industrial premises and easyapproach by the staff controlling the various parts of the weighingdevice in view of maintenance, repairs and releasing blockages in thefeeding of material.

A radial weighing assembly of the type currently known is shown in FIG.1 attached hereto, where said weighing system, denoted by referencenumeral 10, is seen as inserted in a packaging machine, in this case inthe form of a bag-filling machine. The known weighing assembly thereforeessentially comprises a framework 2 supporting, from the top downwards,a central loading hopper 4 designed to receive from above, for examplevia a loader 5, said articles 3 to be packaged, and an upper unit 6 fordistribution of the articles to be packaged which comprises a pluralityof radial channels 8 designed to convey the articles received in acentral position from the hopper 4 towards a plurality of weighingbaskets, denoted overall by reference numeral 12, placed peripherallyand ordered vertically on several weighing levels, designed to defineportions of article to be packaged of a preset weight. More particularlysaid baskets are known as: those of the upper level 12a as prebatchingbaskets, those of the middle level 12b, which carry out actual weighingof the product, weighing baskets, and those of the lower level 12c asauxiliary baskets.

In traditional weighing assemblies said baskets 12 allow the weighedportions of article to drop into a cone 13 which conveys the "weighed"product to be packaged towards the other units of the packaging machine,denoted overall by reference numeral 14 in FIG. 1. In said conveyingcone 13 the product, after a sharp drop onto the highly slanting wallsof the cone, converges fast through gravity towards a narrow lowerdischarge outlet, sliding and rolling along the conical slide surface.

By using the known weighing assembly the articles to be packaged arethen moved to the other parts of the packaging machine by means of afilling tube 16, which in the bag-filling machine shown is used to takesaid predefined portions to be packaged inside, and on the externalsurface a tubular strip 17 in a heat-sealable plastic material formingthe material for making up the packaging bag. Downstream of this fillingunit 16 a unit 18 is provided for sealing and cutting the heat-sealabletubular strip whereby actual individual packages of product 19 areformed.

The weighing assemblies of the known type referred above have anoperational limit represented by the impossibility of using them topackage fragile articles or materials.

By way of an example, by fragile articles we refer for example toproducts of the food industry, such as for example some types ofbiscuits and the like which, if subjected to impact and blows, break andcrumble easily thus becoming unsuitable for sale to the public. It mustnevertheless be understood that each product likely to be broken ordamaged following impact comes under the definition of fragile productsused here.

The impossibility of using these known weighing assemblies for fragileproducts is due to the fact that, during the packaging route whichoccurs progressively from the top downwards, said articles undergo blowsand sudden drops which cause breakage or damage thereof.

It has been found that a particularly damaging element for theintactness of fragile articles to be packaged consists of said conveyingcone 13 situated below said weighing baskets 12.

At said cone the product, which already falls with a certain violenceonto the conical conveying surface thereof, drops virtually freely alongthe strongly slanting conveying walls of the cone, not thereforeundergoing any particular deceleration, but instead acceleratingconsiderably due to the thrust of the force of gravity.

Moreover, as shown in full detail in FIG. 1, the articles 3 forming theweighed portion released by the baskets 12 converge all together towardsthe lower central discharge outlet of the cone 13 where they collidereciprocally and, due to the large quantity of energy accumulated insidesaid conveying cone, break and/or crumble. The articles to be packagedthen pass, with considerable force due to the high speed accumulated inthe cone, to the next filling tube, where due both to further reciprocalcolliding and due to the impact along the internal wall of saidbag-filling tube 16 and with the packaging in heat-sealable plasticmaterial they are further damaged.

In order to overcome these disadvantages, it is unthinkable to build theconveying cone with walls for sliding of the articles with a smallgradient as this would prevent the articles to be packaged from sliding.

Moreover, the use of this conveying cone having a single centraldischarge for the articles forces weighing assemblies to be built with asingle packaging line and moreover such that said packaging units areplaced necessarily below said weighing units. The current weighingsystem with baskets placed peripherally, using said discharge cone, thusheavily restricts the design decisions relating to the arrangement andstructuring of the underlying bag-filling units of the packagingmachine.

The object of the present invention is therefore that of providing aweighing assembly having an improved system for transporting thearticles to be packaged such as to allow packaging without damage evenof so-called fragile articles.

More particularly the object of the present invention is that ofproviding a weighing assembly of the type referred above wherein the useof said conveying cone which causes breakage of the fragile product tobe packaged is avoided.

Another object of the present invention is that of providing a weighingassembly structure which is extremely versatile, such as to allow usethereof in association with more than one packaging line, that is to sayin association with a packaging line placed in a position other than thecentral one, unlike the case for weighing devices of the type withradial development known hitherto.

SUMMARY OF THE INVENTION

The previous objects are achieved, by providing a weighing assembly ofthe type comprising a support framework, hopper means placed centrallyfor central loading of the articles to be packaged, channel means forconveying radially said articles received centrally from said hopper,means for weighing the articles to be packaged, suitable for providingweighed portions to be packaged of said articles, in the form of aplurality of weighing baskets placed peripherally and fed to saidarticles by said channel means and having lower outlets for dischargingsaid weighed portions of said articles and, below said weighing baskets,means for conveying said weighed portions of said articles received viasaid lower discharge outlets of said weighing baskets, characterised inthat said means for conveying comprise at least a first part for theperipheral transport of the articles having a surface for support andtransport of the articles to be packaged positioned below and inproximity of the transfer outlets of corresponding weighing baskets,said transport surface of said first transport part developing along aperipheral conveying path and having an end for transfer of thearticles, and in that means are provided for driving the sequentialmovement of the articles on said transport surface of said firsttransport part towards said transfer end.

In this way it is possible to feed said articles forming said weighedportion to be packaged in sequence towards the weighing units wheretothe weighing assembly is associated. Therefore the reciprocal collidingbetween said articles and the virtually free falling of the articlesdoes not occur, unlike the case in conveying cones of known weighingassemblies.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention and further advantages thereof will be madeclearer on reading of the following description, relating to preferredembodiments of the invention, to be read with reference to theaccompanying drawings, in which:

FIG. 1 is a side elevation view of a packaging machine using a weighingassembly according to the prior art;

FIG. 2 is a perspective view of a significant detail of a firstpreferred embodiment of the weighing assembly of the present invention;

FIG. 3 is a lateral schematic view of a significant detail of a secondpreferred embodiment of the weighing assembly of the present invention;

FIG. 3A is a sectioned schematic view relating to a detail of theintermediate holding baskets of the second preferred embodiment of thepresent invention;

FIG. 4 is a schematic view from above relating to the second preferredembodiment of the weighing assembly of the present invention;

FIG. 5 is a lateral schematic view of a significant detail of a thirdpreferred embodiment of the weighing assembly of the present invention;

FIG. 6 is a schematic view from above relating to the third preferredembodiment of the weighing assembly of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

The weighing assembly of the present invention has, as regards thecharacteristics relating to the central loading hopper, the radialdistribution channels below the latter and the composition andconfiguration of the weighing baskets, substantially the same featuresof the known weighing assembly shown in FIG. 1. Said features are nottherefore described or shown in detail with reference to the preferredembodiments of the weighing assembly of the present invention describedhereinunder.

As mentioned, FIG. 2 shows a significant detail of a first preferredembodiment 20 of the weighing assembly of the present invention thatincludes a radial channel device 22 whereby the articles to be packagedreceived in a central position from the upper loading hopper (not shown)are transferred radially towards peripheral baskets 24 of a unit 26 forweighing portions to be packaged. Said weighing unit 26 being of thetype disclosed in EP-A-0 747 679. Said baskets 24 are controlledautomatically by a computer in such a way that, when the overall weightweighed by a random combination of baskets gives as a sum the weight ofthe preset portion to be packaged, the baskets concerned are opened toallow discharge of said weighed portion.

As shown in detail with reference to this first embodiment of a weighingassembly, according to the present invention a first and a secondperipheral transport part 28, 30 are provided below said weighingbaskets 24 and have respective semicircular and horizontal surfaces 32,34, coplanar one with the other, for supporting and transporting thearticles to be packaged.

As shown, said surfaces 32, 34 for supporting and transporting arepositioned near the lower transfer outlets of the corresponding weighingbaskets 24, in such a way that the product does not gain in speed byfalling from said baskets but instead rests gently on said transportsurfaces 32, 34 without risks to the safety of the articles.

Said transport surfaces 32, 34 allow the articles to be transported in asequential manner, and deposited in groups or individually in variouspoints of the transport surface, along a peripheral conveying pathtowards respective transfer ends 36, 38 where, by falling, said articlespass through the entrance aperture 40 of the tube 42 for filling andguiding for the heat-sealable strip whereto the weighing assembly isassociated. Said tube 42 is wholly similar to the filling and guidingtube 16 for the heat-sealable strip of the bag-filling machine shown inFIG. 1 and has therefore only been shown partially.

Advantageously said peripheral transport parts 28, 30 are in the form ofendless conveyor belts, wherein the belt 44, 46 defines said surface forsupport and transfer of said articles. Said conveyor belts are driven torotate by means of respective suitable motors 47, 49 in such a way as todrive the sequential movement of the articles placed on said transportsurface of said first transport part towards the respective transferend.

According to the present invention, said transport parts could howeveralso be made in the form of peripheral surfaces with vibration or inanother suitable manner.

As shown, in accordance with a further advantageous feature of thepresent invention, the weighing assembly of this first embodiment alsocomprises a channel 48 for conveying articles, having an upper surface50 for sliding of said articles, which is placed below said transportsurfaces 32, 34 of said first and second transport parts 28, 30, at thetransfer ends 36, 38 of the latter. Said channel 48 conveys thearticles, through the force of gravity, towards the entrance 40 of saidfilling means.

The elimination of the traditional central discharge cone thus allowsthe weighing assembly of this first preferred embodiment to feed theproduct towards an entrance 40 of the filling tube positioned radiallyoutside of said weighing baskets 24. In order to feed said entrance 40of the filling tube outside of said weighing baskets, the conveyingchannel 48 extends radially outside of said channels.

Obviously it can also be foreseen for the present invention to positionsaid conveying channel 48 towards the interior of the weighing assemblyso as to convey the product towards an entrance of the conveying tube ofthe packaging machine placed in a central position as is the case forthe packaging machine according to the prior art.

FIGS. 3, 3A and 4 show a second preferred embodiment of the weighingassembly according to the present invention. This second preferredembodiment has various similarities with said first preferredembodiment. The elements of this second preferred embodiment which aretherefore wholly similar or equivalent to those of the first are denotedin the figures by the same reference numerals of the latter and, inorder not to overburden this description, they are not commented onagain in detail.

In particular FIGS. 3 and 4 show an upper loading hopper 21, and anelement 23 for deviation or transfer of the articles leaving the loweroutlet of said hopper centrally towards the radial transfer channels 22,which in turn transfer the articles to the weighing baskets 24 placedperipherally.

This second embodiment also comprises a first and a second peripheraltransport part 28, 30 for the articles received from the weighingbaskets 24 having respective ends 36, 38 for transfer towards aconveying channel below the latter.

This second preferred embodiment differs from the first preferredembodiment mainly due to the fact that it has, below said transportsurfaces 32, 34, at the transfer ends 36, 38 thereof, respective parts52, 54 for storage and temporary holding of articles to be packaged, inthe form of collection baskets suitable for receiving in sequence thearticles from said respective first and second transport parts 28, 30 tobe held by these baskets 52, 54 for a certain time and then released,via respective lower transfer outlets, driven by suitable means forcontrolling opening/closure of said transfer outlets of a kind alreadyknown in the art and therefore not shown in the figures.

As shown schematically in FIG. 3A, with reference to the intermediatebasket 52 alone in the embodiment shown, said intermediate collectionbaskets 52, 54 have their respective lower transfer outlets placed inproximity of the respective slide surfaces 50 of said conveying channel48. Said FIG. 3A shows in particular and schematically the basket withthe closure doors 52a, 52b in an open condition for release of thearticles towards said channel 48.

Naturally according to the present invention it could also be foreseennot to use such a conveying channel 48. Said intermediate holdingbaskets in this case would discharge directly into said opening 40 forfeeding into said tube 42 for filling and guiding for the heat-sealablestrip.

These temporary holding baskets 52, 54 therefore allow the drop of thearticles to be stopped temporarily, and thus the latter are slowed downand fall onto the underlying surface with less kinetic energy. Theproximity of the underlying slide surface 50 of the conveying channel 48is a further guarantee against violent impact and resulting breakage.

FIGS. 5 and 6 show a third preferred embodiment of the weighing assemblyaccording to the present invention.

Also in this third preferred embodiment the elements similar orequivalent to those of the first two embodiments are denoted by the samereference numeral.

This third preferred embodiment of a weighing assembly has, in adistinctive manner compared to the previous embodiments, second fillingmeans having a respective tube 56 for feeding the articles with arespective inlet opening 58. Said inlet 58 of said second filling meansis the same as the first filling means 56 placed outside of theperimeter of said weighing baskets on the side of the weighing assemblyopposite to that of the first filling means 40.

In order to feed articles also to this second packaging unit using asingle weighing assembly, according to the invention, a second channel60 for conveying the articles is provided, placed on the side oppositeto that of the first conveying channel 48, and having a respectivesurface 62 for sliding of said articles, which surface is positioned, atthe transfer end 38' of said second transport part 30', below saidtransport surface 34' of said second peripheral transport part 30'.

This second conveying channel 60 also extends, like the first, radiallyoutside of said weighing baskets to convey the articles to be packagedtowards the entrance 58 of said second filling means situated radiallyoutside of the perimeter of said weighing baskets.

In this third embodiment the intermediate holding basket 54',discharging the articles collected thereby onto the slide surface 62 ofsaid conveying channel 60, is then positioned on the opposite side tothat whereon the first basket 52 is positioned.

The transport part 30' of this third preferred embodiment thentransports the articles, on its support and transport surface 34', in anopposite angular direction to that of the similar conveyor belt 30 ofthe two previous embodiments, having as transfer end 54' the oppositeend to the one 54 used for transfer of the conveyor belt of the previousembodiments.

From what has been shown hitherto it is clear that the present conceptof weighing assembly could also cover weighing assemblies suitable forserving a plurality of peripheral packaging units served by respectiveperipheral transport parts of the weighing assembly, which can extendperipherally for a fraction of circumference and are placed belowcorresponding weighing baskets.

According to the type of material to be packaged the conveyor belt canbe made in cloth, plastic material or metal mesh in order to have anextremely soft and flexible surface for supporting the articles and thusavoiding any further risk of damage to the articles themselves.

It must also be understood that what has been written and shown withreference to the preferred embodiments of the present invention has beengiven purely as a non-limiting example of the principle claimed.

I claim:
 1. A weighing assembly comprising a support framework, hoppermeans placed centrally for central loading of the articles to bepackaged, channel means for radially conveying said articles receivedcentrally from said hopper, means for weighing the articles to bepackaged, suitable for providing weighed portions to be packaged of saidarticles, in the form of a plurality of weighing baskets placedperipherally and fed to said articles by said channel means and havinglower outlets for the discharge of said weighed portions of saidarticles and, below said weighing baskets, means for conveying saidweighed portions of said articles received via said lower dischargeoutlets of said weighing baskets, wherein said conveying means compriseat least a first part for peripheral transport of the articles having asurface for supporting and transporting the articles to be packagedpositioned below and near the transfer outlets of corresponding weighingbaskets, said transport surface of said first transport part defining aperipheral conveying path and having an end for transfer of thearticles, and wherein means are provided for driving the sequentialmovement of the articles on said transport surface of said firsttransport part towards said transfer end.
 2. A weighing assemblyaccording to claim 1, wherein it comprises a first channel for conveyingof the articles having a slide surface for said articles placed, at thetransfer end of said first transport part, below said transport surface.3. A weighing assembly according to claim 1, wherein it comprises a partfor temporary storage of the articles to be packaged, placed below saidtransport surface at the transfer end thereof.
 4. A weighing assemblyaccording to claim 3, wherein said part for temporary storage of thearticles to be packaged is in the form of a collection basket suitablefor receiving articles from said first peripheral transport part andhaving a lower outlet for transfer of the articles contained, and inwherein means are provided for opening and closing said outlet fortransfer of the articles to be packaged.
 5. A weighing assemblyaccording to claim 2, wherein said transfer outlet of said intermediatecollection basket is placed near the slide surface of said conveyingchannel.
 6. A weighing assembly according to claim 2, wherein saidconveying channel extends radially outside of said weighing baskets toconvey the articles to be packaged towards the outside of said weighingbaskets.
 7. A weighing assembly according to claim 1, wherein said firsttransport part is an endless conveyor belt whose belt defines saidsurface for supporting and transporting said articles.
 8. A weighingassembly according to claim 1, wherein said transport surface of saidfirst peripheral transport part lies on a horizontal plane.
 9. Aweighing assembly according to claim 1, wherein said conveying meanscomprise a second part for peripheral transport of the articles having asurface for supporting and transporting the articles to be packagedpositioned below and near the transfer outlets of corresponding weighingbaskets, said transport surface of said first transport surfacedeveloping along a peripheral conveying path and having a respective endfor transfer of the articles to be packaged; and in wherein means areprovided for driving the sequential movement of the articles on saidtransport surface of said second transport part towards said transferend.
 10. A weighing assembly according to claim 9, wherein said secondtransport part has its transfer end above said first conveying channelin a frontal position in relation to the transfer end of said firsttransport part.
 11. A weighing assembly according to claim 9, wherein itcomprises a second part for temporary storage of the articles to bepackaged placed below said transport surface of said second transport atthe transfer end thereof.
 12. A weighing assembly according to claim 11,wherein said second part for temporary storage of the articles to bepackaged is in the form of a collection basket suitable for receivingthe articles from said first peripheral transport part and having alower outlet for transfer of the articles contained, and in whereinmeans are provided for opening and closing said outlet for transfer ofthe articles to be packaged.
 13. A weighing assembly according to claim12, wherein said transfer outlet of said second temporary collectionbasket is placed near the slide surface of said first or said secondconveying channel.
 14. A weighing assembly according to claim 9, whereinit comprises a second channel for conveying articles placed on the sideopposite to that of said first conveying channel and having a respectiveslide surface for said articles positioned, at the transfer end of saidsecond transport part, below said transport surface of said secondperipheral transport part, and suitable for conveying through gravitythe articles to be packaged.
 15. A weighing assembly according to claim14, wherein said second conveying channel extends radially outside ofsaid weighing baskets for conveying the articles to be packaged towardsthe outside of said weighing baskets.
 16. A weighing assembly accordingto claim 9, wherein said second transport part is in the form of anendless conveyor belt.
 17. A weighing assembly according to claim 9,wherein the surface for supporting and transporting said secondperipheral transport part lies on a horizontal plane.
 18. A weighingassembly according to claim 1, wherein said transport surfaces of saidfirst and second transport parts lie on the same horizontal plane.
 19. Aweighing assembly according to claim 1, wherein each of said transportsurfaces of said first and second transport parts extends for asemicircular section.
 20. A weighing assembly according to claim 4,wherein said first and second temporary holding baskets are positionedon opposite sides of said conveying means.
 21. A weighing assemblycomprising:plural radial channels for receiving articles to be packagedand conveying them radially outward; means for weighing articles to bepackaged, said means for weighing including plural weighing baskets thatare peripheral to said channels, each of said baskets for receivingarticles to be packaged from at least one of said channels, each of saidbaskets having a lower outlet; a movable, semicircular conveying paththat passes beneath said lower outlets of said baskets and receivesarticles to be packaged therefrom, said conveying path having an end;and a receptacle at said end of said conveying path for receivingarticles to be packaged from said conveying path.